<template>
<div>
  <router-link
    tag="div" to="/"
    class="header-abs"
    v-show="showAbs"
    :style="opacityStyle"
  >
    <div class="iconfont header-abs-back">&#xe624;</div>
  </router-link>
  <div class="header-fixed"    v-show="!showAbs">
    <router-link to="/">
      <div class="iconfont header-fixed-back">&#xe624;</div>
    </router-link>
    景点详情
  </div>
</div>
</template>

<script>
export default {
  name: 'DetailHeader',
  data () {
    return {
      showAbs: true,
      opacityStyle: {
        opacity: 0
      }
    }
  },
  methods: {
    handleScroll () {
      console.log('scroll')
      const top = document.documentElement.scrollTop
      if (top > 60) {
        let opacity = top / 140
        opacity = opacity > 1 ? 1 : opacity
        this.opacityStyle = {
          opacity
        }
        this.showAbs = false
      } else {
        this.showAbs = true
      }
      console.log(document.documentElement.scrollTop)
    }
  },
  // 钩子函数
  activated () {
    window.addEventListener('scroll', this.handleScroll)
  }
}
</script>

<style scoped lang="stylus">
  @import '~styles/varibles.styl'
  .header-abs
    position: absolute
    top:.2rem
    left:.2rem
    width:.8rem
    height:.8rem
    line-height: .8rem
    text-align: center
    border-radius: .4rem
    background: rgba(0,0,0,0.8)
    .header-abs-back
      color: #fff
      font-size:.4rem
  .header-fixed
    z-index: 2
    position: fixed
    top: 0
    right:0
    left: 0
    line-height: $headerHeight
    height:$headerHeight
    background:$bgColor
    text-align: center
    color: #fff
    font-size:.32rem
  .header-fixed-back
    position: absolute
    top: 0
    left: 0
    width:.64rem
    font-size:.4rem
    color: #fff
    text-align: center
</style>
